659-1 Characterization of Fungal Endophytes Present in Elymus Canadensis (Canada wildrye).

Tuesday, 7 October 2008
George R. Brown Convention Center, Exhibit Hall E
Carolyn Young, Shipra Mittal, Cindy Crane and Andrew Hopkins, The Samuel Roberts Noble Foundation, Ardmore, OK
Elymus canadensis (Canada wildrye - CWR) is a native perennial cool season bunch grass that tolerates a range of soils, is winter hardy and able to grow as far North as Southern Alaska.  Canada wildrye is used for prairie restoration and conservation, and young CWR plant tissue is palatable and nutritious to grazing animals.  Canada wildrye has been previously reported to harbor the sexual epichloë endophyte, Epichloë elymi, which is known to produce stromata that choke emerging inflorescences. We have isolated and characterized epichloë endophytes from three endophyte-infected CWR accessions collected from Mexico (1 strain) and Texas (2 strains).  Phylogenetic analysis of the tefA and tubB genes established that the endophytes present in these CWR accessions are interspecific hybrids with E. elymi and E. amarillans ancestral parents.  These data indicate that the epichloë isolates are asexual and will be vertically transmitted through seeds. PCR analysis was used to determine the alkaloid potential of each endophyte using markers to identify biosynthesis genes for peramine, lolines, ergot alkaloids and indole-diterpenes. This data suggested that the CWR endophtyes should be able to produce peramine and a loline precursor but not the indole-diterpenes.  Unlike the strains isolated from Texas, analysis of the ergot alkaloid biosynthesis genes indicated that the strain isolated from Mexico did not contain the complete gene complement and would be unlikely to produce the mammalian toxin ergovaline. HPLC analysis of endophyte-infected plant material confirmed that the two endophyte strains from Texas were able to produce ergovaline in planta, while the strain from Mexico was only able to produce chanoclavine, a known ergovaline precursor.  Endophyte-infected plant material will be analyzed for field persistence and animal safety.